Lightning arrester and heat coil



Sept. 25 19.23. 1,468,650

R. G. SANDS LIGHTNING ARRESTER AND HEATCOIL Filed May 28 1919 .man

Patented Sept. 25, 1923.

.UNITED STATES 1,468,650 PATENT OFFICE.L

ROY GRANVILLE SANDS, OF WUKEGAN, ILLINOIS, ASSIGNOR TO FRANK B. COOK COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

LIGHTNING ABRESTER AND HEAT COIL.

Application led May 28,

To all whom it may concern:

Be it known that I ROY GRANVILLE SANDS, a citizen of the United States, residing at lVaukegan, in the county of Lake and State of Illinois, have invented new and useful Improvements `in Lightning Arresters and Heat Coils, of which the yfollowing is a full, clear, concise, and exact description, reference bein had to the accompanying drawing, forming a part of this specification.

This invention relates to av combination lightning arrester and heat coil and more particularly to an `improvement inthe construction of combination li htning arresters and heat'coils used for te protection of telephone and telegraph circuits.

Telephone and telegraph circuits' must be protected against high potential and abnormal current and for this purpose the incoming lines are each wired to a combination lightning arrester and heat coil. Combined heat coil and lightning arrester units are generally assembled in strips, in which a plurality of such units are mounted on a mounting plate, which serves the double purpose of mounting plate and ground bar.

One of the objects of this invention resides in the production of an improved combination lightning arrester and heat coil construction which is composed of few parts and is simple in construction.

Another object consists in the production of an improved construction which will kcheap'en the cost of construction and which will materially reduce the work required to assemble the units.

A. further object resides in the production of means to automatically limit the setting of the heat coil between certain determined limits.

An additional object consists in the production of a heat coil operating spring of increased flexibility.

Other objects of the invention will become apparent from the following description and the appended claims.

The invention is illustrated in the accompanying drawing in which:

Fig. 1 is a side view of an arrester and heat coil mounting' strip with a plurality of heat coil and lightning arrester units mounted thereon;

Fig. 2 is a view in cross-section, taken on the plane represented by the line 2-2 of 1919. Serial NO. 300,435.

Fig. 1 looking in the direction of the arrows;

Fig. 3 is a cross-section through the heat coil taken on the plane represented by the line 3 3 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is an enlarged detail construction illustrating the lugs which are upset on the mounting plate and the correlated position between said lugs and the spring assembly mounting bolt;

Fig. 5 is a section taken on the plane represented by the line 5 5 of Fig. 4 looking in direction of the arrows; and

Fig. 6 is a View in perspective of the carbon block and its associated spring and illustrates the slot cut in the carbon block to accommodate a tooth pick which is used for cut-over and testing'purposes.

As illustrated in the drawings the base plate used for mounting the arrester unit and which also functions as the ground plate comprises two sheet metal plates 10 and 11, provided with a plurality of perforations such as 12, which serve to receive screws such as 13 or any other securing means for holding the fiat surfaces of these plates 10and 11 together. The plates are separated and become divergent at 14, being separated sufficiently to conveniently accommodate the heads 15 and 16 of bolts 17 and 18 respectively, and the heads 19 and 20 of bolts 21 and 22 respectively, which bolts are utilized to secure the spring assembly on the plates 10 and 11. The sheet metal plates 10 and 11 are perforated in divergent sections thereof to provide holes such as 23 for the bolts 17, 18, 21 and 22. The springl assembly for each line wire is secured to the plate, either 10 or 11 by bolts such as 17 and' 21 as illustrated in Figs. 1 and 2. In making the perforations in the plate to obtain the holes 23 into which the bolts are inserted, the metal is upset to form a lug on on either side of each hole, as clearly illustrated inthe details of Figs. 4 and 5. The lugs 24 cooperate with the square heads 15, 16, 19 and 20 of the bolts to prevent the bolts from turning in the hole perforations 23 when the bolt has been inserted in the perforations so that the head of the bolt strikes against the inner surface of the plates and the upset lugs 24 are aligned adjacent the heads of said bolts.

In assembling the ground plates for the arrester and heat coil mounting the holes or perforations 23 in the plates 10 and 11 are each first fitted with a spring assembly bolt. After all the perforations i3 have received the bolts, the two plates are placed together as shown in Fig. 2 and secured together by means of the screws 13 or any other convenient fastening means, such as rivets. lhen the plates are thus held together it will be evident that the bolts will be held in position since the heads 15 and 16 of the adjacent bolts 1T and 1S have their upper surfaces substantially in contact and likewise the upper surfaces of the heads 19 and 2O of the adjacent bolts 21 and 22 have their upper surfaces substantially in contact. This is also true of all the bolts in the mounting plate and hence movement in the direction of the length of the bolts when the plates 10 and 11 are interconnected is substantially eliminated. The bolts are thus positivelyY held in position in the plates against longitudinal and vertical movement when once assembled. Likewise rotary moven'ient of the bolts is prevented by the upset lugs 2l which fit against the square faces of the bolt as clearly indicated in Figs. 4 and 5.

It will now be evident that when the two plates 10 and 11 have been connected by the binding screws 13 with the bolts 1T, 1S, 21 and 22 utilized to mount the spring assembly for eac-h pair of wires in position on the ground plate. that the bolts will be positively held against longitudinal as well as rotary movement and consequently the mounting of the springs and necessary insulators between the springs on these bolts is a comparatively easy operation. Likewise since the plates 10 and 11 are punched sheet metal plates the perforations for the bolts, as well as the perforations for the screw which secure the plates together. as well as the lugs such as 23 used to guide the carbon 29 on the ground plate, can all be performed in the punch press blanking and forming operations, which therefore makes the production of the mounting plate a comparatively cheap operation.

lVhen the two pla-tes 10 and 11 are assembled with the respective spring assembly mounting bolts positioned in the diverging ends of said plates, the various springs including the grounding spring 29', the heat coil mounting spring 30, which also serves to support the carbon blocks 29 in place, the heat coil operating springs 31 and the various associated and interconnected springs and insulating washers can be readily slipped in place on the bolts and secured in position by nuts such as The function of the various springs shown in the drawings are well known to those skilled in the art, and consequently a. detailed description thereof herein is considered unnecessary,

The heat coil operating spring 31, is twisted through an angle of 90 degrees atl substantially the middle point 31 of the free or movable part of said spring. The twisting of the spring 31 at this point materially increases its iexibility and thereby facilitates movement of the spring from and toward the heat coil 33, and movement at substantially right angles to such movement. This movement of the spring at right angles to the movement of the sprinff from and towards the heat coil is conneil substantially to that part of the spring situated above the twist 31', whereas the movement of the spring from and toward the heat coil is imparted to the entire free end of the spring positioned above the insulating mounting plates. Due to this twist in the spring 31, therefore, free movement is given to the said spring in two directions at right angles to one another to the extent required for the successful operation of said 'spring The twst in the spring 31 consequently increases the spring flexibility and reduces the strain on the spring, and also the strain exerted on the spring mounting means.

The heat coil spring 30 carries the heat coils 33, said heat coils being equipped with the usual heating element to heat the fusible alloy to a fluid state when an excessive current continues to flow through said coil` and whereby the outer shell of the coil is loosened. This outer shell 35 fitted with ieripheral teeth 36. is thus permitted to turn. The construction and operation of heat coils of this type are well understood by those skilled in the art and consequently no further description thereof is given herein.

As is well understood in the art. the heat coil operating spring 31 is biased to normally assume the position shown in the broken lines in Fig. Q. Then in this position the spring 29 will ground the spring 30 which through terminal Contact 40 is connected to the line. In the normal operating position of the apparatus, however, when the heat coil operating spring is in the position shown in full lines in Fig. 2, the insulating pin 41 is pushed by heat coil operatingr spring 31 against the grounding spring E29I and breaks contact between said spring Q9 and the spring 30 thus freeing the line wires from ground. The heat coil operating spring is held in this position by a notch 44, pressed out of the upper portion of the spring 31, which notch catches in one of the teeth 36 in the outer peripheral surface of the heat. coil.

Obviously when the heat coil is operated and the peripheral shell thereof is permitted to turn, the spring tension of the spring 31 will turn said surface to free the notch 44 from the tooth to allow the spring 31 to take its operated position as shown in broken lines in Fig. 2. When the grounded condition of the line has been removed and it is desired to reset the coil, it is merely necessary to force spring 31 forward toward the heat coil, at which time the upset latch or lug 44 will catch in a tooth,'thereby closing the circuit through the heat coil andcheat coil spring to the switch board terminals The method of heat coil operation just described in which the heat coil operating spring is pressed forward to permit the lug on said spring to catch one of the teeth in the heat coil is well known and old in the art With this type of heat coil and spring difficulty has been experienced, however, in attaching the lug 44 in a tooth 36 on the shell of the heat coil positioned on the inner quadrant of the coil and at a point several teeth removed from the position at which the spring Acontaining the catch 44 is tangent to the coil. Under these circumstances it frequently happens because of the'very inadeuate and poor contact with the spring 31, t at'due to jars, the said spring is released from the tooth with which it was engaged and thus a grounded condition of the particular line wire is indicated because of the unlatching between the heat coil and the heat coil operatingspring.

To eliminate this difficulty the heat coil springhere shown is fitted with a protruding element or hump 49 punched out of the part 45 of the coil operating spring 31. This protruder or hump in the spring is so designedthat it will ride over the ends of the teeth on the peripheral surface ofthe coil after the catch 44 has passed over the end of the tooth which is positioned at the point in the peripheral surface of the coil substantially tangent to the plane of movement of the operating spring 31. f

The catch 44 in the design of spring here shown, provided with the protruding element 49, can consequently only catch the tooth which is positioned at the point in the peripheral surface of the coil substantially tangent to the plane of movement of the operating spring 31 and the one just preceding it. This, therefore, prevents a faulty or defective engagement between the catch 44 and the teeth of the heat coil and conse-V quently it is substantially impossible to disengage the catch 44 from the teeth exceptby the blowing of the coil or a deliberate manual act separating the catch 44 from the heat coil.

In the heat coil operating spring designed with this hump 49 the grounding of the line due to defective engagement between the heat coil operating spring and theheat coil is avoided, inasmuch as the rsetting of the heat coil operating spring with respect to the teeth of the heat coil is automatically restricted between certain determined limits.

Fig. 6 shows an improvement in the carbon block utilized next to the spring 30, which is utilized in cut-overs in which grounding of the line will be prevented before setting the heat coil. For this purpose carbon block 29 is provided with the additional slot 50 of size suiii'ciently large to ac commodate a peg of insulating material, a tooth pick 51 usually being employed which may be inserted into the slot 50. When the tooth pick is thus inserted in the slot 50 it is pushed' down far enough along the surface of the spring 30 so that when the heat coil operating spring 31 is in the position it normally assumes when not attached to the heat coil the grounding spring 29 will contact ywith the wooden surface of the tooth pick and not with the metallic surface of the spring 30. In cut-overs, that is when a new exchange or new section of a telephone exchange is to be put into operation, all the connections are made, except the connection at the heat coil, at which point the circuits are retained in an open condition by retaining the heat coiloperating spring in the blown position as shown in broken lines in Fig. 2. Under these circumstances with the tooth picks inserted as shown in Fig. 6 none of the lines will be grounded due to contact between the spring 29 and the grounding spring. The moment that it is desired to cut the lines into service, all the heat coils are set which closes the line connections and completes the cut-over, after which the tooth picks can be readily removed without interfering with the circuit connection.

It will now be evident from the foregoing description that combination lightning arrester and heat coil units constructed in accordance with the teachings of this invention are made of a minimum number of simple parts which are very easily assembled Likewise the parts are so correlated that faulty operation thereof is reduced to a minimum.

The invention is obviously not limited to the specific embodiments thereof herein illustrated and described but is capable of other applications and many variations within its spirit and scope set forth in the following claims.

Having thus described my invention, what I claim as new and desire to obtain by Letters Patent is:

1. In a combination lightning arrester and heat coil unit, a mounting plate provided with perforations, lugs upset from said plate adjacent to said perforations, a spring assembly mounted on said mounting plate, bolts extending through said perforations and adapted -to retain said spring assemblies in position, said bolts being provided with square heads which cooperate with said lugs to prevent turning movement of said bolts.

2. In a device of the character described,

mounting means consist-ing otV two plates provided with perforations, lugs upset from said plates, square-headed bolts iitted in said pertorations in each ot said plates and ell'ecting engagement between the square heads and said lugs, and means for securing said plates together tace to "face, whereby said bolts will be held in position in said plates.

3. In a device ot the character described, a n'iounting means consisting ot two plates provided with perfor-ations, lugs upset from said plates, bolts fitted in said periforations held in place by said lugs, and means to secure said plates together' tace to tace whereA by said bolts will be held in position in the pertorations in said plates.

In a device ot' the character described, a mounting means consisting of two plates, lugs upset from said plates adjacent to perfor-ations formed in said plates, bolts fitted in said perforations and held in place by said lugs, and means to secure said plates together tace to tace whereby said bolts will be held in position in the per'torations in said plates, the heads of said bolts being rectangular in shape to cooperate with said lugs to prevent turning movement of the said bolts.

5. In a device of the character described, a mounting means consisting` of two plates provided with periiorations and interconnected face to face and with the plates separated and diierging at one end, upset lugs pressed out ot said plates and projecting forwardly 'from said plates at the diverging ends thereot', securing bolts fitted into the perfor-ations in said plates caused by the upsetting of said lugs, said upset lugs so cooperating with the heads of said bolts to pre ent turning movement of said bolts, and a spring assembly mounted on each of said plates and secured thereto by said bolts.

6. rilhe method of mounting spring assemblies l'or arrester and heat coil units on ground plates which consists in iitting the securing bolts for spring assemblies in each of two plates, then securing the plates together face to face to hold the bolts in place and thereafter placing the spring assemblies on said bolts and securing them to said plates. A

T. In a device ot the character described in combination, a heatcoil having a toothed exterior peripheral surface, a heat coil operatingy spring cooperating with the teeth on said surface, and means cooperating with said teeth to permit engagement of the cooperating elements between said spring and said teeth, only in the teeth tangent to the advancing spring and the tooth next preceding said tooth.

S. In a device of the charac-ter described in combination, a heat coil having an outer peripheral surface consisting of teeth, a heat coil operating spring, means associated with said operating spring which cooperates with the teeth on said heat coil, and means associated with said spring for automatically limiting the setting of the cooperating elements comprising a latch on said spring and the teeth on said coil between certain determined limits.

9. In a device of the character described in comi ination, a heat coil having an exterior suriace comprising a plurality ot teeth, a heat coil operating spring cooperating with said teeth, a catch in said spring cooperating with said teeth for setting the heat coil operating spring, and a protruding element in said spring adjacent said catch which limits the cooperation between the catch and the teeth ofthe heat coil within certain defined limits of peripheral tooth circumference.

l0. In a device of the character described, a spring mounting means, a heat coil` and a heat coil operating' spring, said spring having a twist at substantially the middle portion of the Lt'ree end thereof whereby increased flexibility is iniparted to said spring in two directions transverse to each other.

Il. In a device of the character described, a spring mounting means. a heat coil and a heat coil operating spring, said spring having a right angular twist at substantially the middle portion otl the free end thereoi" whereby increased lexibility is imparted to said spring in two directions substantially at right angles to each other.

l2. In a combination lightning arrester and heat coil, a mounting structure comprising aplurality ol opposed sheetmetal plates severally provided with perforations, lugs upset on said plates adjacent to said perforations, corresponding perforations in said plates being opposite to each other, separate bolts projecting outwardly through said perforations and on opposite sides ot said mounting structure, the heads ot opposed bolts abutting each other to prevent longitudin al movement thereof, and severally enga ging said upset lugs t'o prevent turning movement oil said bolts, and spring assemblies secured to said bolts.

13. In a combination lightning arrester and heat coil, a mounting structure therefor comprising a plurality of side-by-side sheet metal plates, mounting bolts severally engaging said sheet metal plates and projecting therefrom 'on opposite sides of said mounting structure, corresponding mounting bolts having their opposed heads in alinement with each otheryto prevent longitudinal movement thereof in the assembled structure, and lugs integrally formed on said plates and engaging each separate mounting bolt to prevent turning movement thereof. and spring assemblies for said mounting bolts.

Ll. In a device of the character described, a mounting structure comprising two sideby-side sheet metal plates severally provided Wit-h opposed perforations, b'olts severally' fitted in said perforations in each of said plates, means for securing said plates together faee-to-faoe whereby opposed bolts will hold each otheragainst longitudinal movement, and upset lugs integrally formed on each of said sheet metal plates and engaging the several bolts whereby each bolt will 1 be separately held against turning movement.

15. The method of mounting spring assemblies for lightning arrester and heat coil units on ground plates Which consists in separately fitting the securing bolts for mounting the spring assemblies upon each of said plates, then securing the plates together face-to-face to hold the separate mounting bolts on opposite sides of said ground plates in place, and thereafter placing the spring assemblies independently on said bolts and securing them to said ground plates.

In Witness whereof, I have hereunto subscribed my name.

ROY GRANVILLE SANDS. 

